Warmth to alter farming

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Palmerston North's second warmest year and warmest winter on record has raised alarm bells, with climate scientists concerned about the effects of prolonged warmth on the region's agricultural base.

But farmers say that even though a warmer Manawatu could harm production for crops such as barley and wheat, and bring new bugs and parasites south, they are confident the effects will not be serious.

Climate scientist Jim Salinger yesterday released figures showing the 2013 winter in Manawatu - and across New Zealand - was the warmest since records began in 1870. The average temperature in Palmerston North in 2013 was 14.1 degrees Celsius, 0.85C above normal.

The only year it was hotter was 1998, when Palmerston North had an average temperature throughout the year of 14.2C.

Winter 2013 mean temperatures mirrored national figures at 1.27C above the 1961-1990 average, the highest on record. Around the country Masterton, Omarama, Timaru, Invercargill and the Chatham Islands all had record years.

Dr Salinger said that while the temperature increase was nice for some, the Manawatu region's reliance on agriculture would be affected in the long term by the warming. The above-average temperatures were expected to continue this year with 0.2C to 0.6C above average temperatures for New Zealand predicted, he said.

"What will start to happen is a spread of sub-tropical grasses that will make farming as it is more difficult. The type of cropping Manawatu relies on will probably change too. As planetary warming continues you'll see more of a move into corn and maize and crops like that.

"They have higher heat requirements but as it gets hotter they will become the future."

The warming followed a global trend which an Intergovernmental Panel on Climate Change report blames on "increasing greenhouse gases augmenting the greenhouse effect", Dr Salinger said.

On Chris Satherley's farm in Linton, the warmth has allowed the best year in 42 years of farming.

The key for the owner of agricultural contractors Joyclas Farms has been the accompanying moisture.

"Pasture growth has just been through the roof in 2013. We started silage in August and normally in Manawatu you don't traditionally get going on that until November," Mr Satherley said.

The drought in early 2013 had shown what warmth without rain could do but with forward planning the region could be better off with extra warmth, Mr Satherley said.

Ironically, maize production was down in 2013 on the farm, although Mr Satherley said chicory was growing better than ever before.

The start to 2014 had also been an "incredible Christmas present" with another 55 millimetres of rain on the paddocks since December 24.

Federated Farmers Manawatu/Rangitikei grain and seed spokesman David Lee Jones said the region could still support a similar amount of agriculture if it was slightly warmer.

"If you look at a place like Waikato . . . if we warm a bit, we'll perhaps be a little like that.

"Grasses will change, there won't be much wheat and barley but there will definitely be more maize."

A focus on improving plant genetics and parasite protection would be critical to combating the effects of warmer temperatures in Manawatu, and the region was already doing well in that regard, Mr Lee Jones said. "We've already seen things like facial eczema, how that has spread, almost around all of the North Island, when that was only found in Northland and Auckland in the depths of World War II.

"Those sorts of bugs that are in warmer areas, things like theileria that is being carried around by ticks in Northland, we could well see that further south. But nothing is happening overnight and I think the changes will be so gradual we might not notice them. Genetics could well keep up with them."